1. Field of the Invention
The present invention relates to a hard disk drive which is capable of recording and reproducing data and is so designed that the hard disk drive becomes particularly compact, space-efficient and light-weight.
2. Description of the Prior Art
A hard disk drive belongs to one of computer-peripheral equipment capable of recording and reproducing data. The hard disk drive is provided with the mechanism in that a magnetic head, operating as a transducer, records and reproduces data, and a rotary actuator moves the magnetic head to designated positions then holds it at such positions.
Based on FIG. 1, the rotary actuator in a conventional hard disk drive is briefly explained as follows.
The hard disk drive contains a base 1 which constitutes a part of a lower housing portion, and on the base 1, a magnetic disk 3 is freely rotatably provided through a spindle motor 5. A pivot 7 disposed in parallel with a rotation axis of the magnetic disk 3 is constructed outside an outer circumference 4 on the base 1. A carriage 9 is freely rotatably coupled to the pivot 7. At one end of the carriage 9 in the direction toward the magnetic disk 3, the magnetic head 13 is provided and is coupled to a suspension 12; a coil 15 is provided at another end of the carriage 9. The magnetic head 13 and the suspension 12 together form a head assembly.
Yokes as a part of a magnetic circuit are provided on the base 1 with the coil 15 located therebetween. A permanent magnet is mounted on one of the yokes to constitute a voice coil motor (VCM). As a result of interaction between the magnetic field generated from the coil 15 and the one from the permanent magnet with a certain level of control currents supplied to the coil 15, a thrust is produced to drive the carriage 9. Thus, in the conventional hard disk drive, the thrust generated in the coil 15 rotates the carriage 9 connected to the coil 15 about the pivot 7 situated outside the outer circumference 4 of the magnetic disk 3, so that the magnetic head 13 mounted in one end of carriage 9 can be positioned to predetermined positions to record/reproduce data to and from the magnetic disk 3.
Recently, in the computer-peripheral equipment, there is a tendency toward making such computer-peripheral equipment utmost compact, space efficient and thereby light weight. This also concerns the hard disk drive. However, as shown in FIG. 1, since the carriage 9 positioning the magnetic head 13 on the magnetic disk 3 is supported by the pivot 7 situated outside the outer circumference 4 of the magnetic disk 3 in conventional hard disk drives, a length L of the hard disk drive is determined by a radius r of magnetic disk 3, a size of pivot p and a size of coil c for a certain size of magnetic disk. Thus, in order to achieve further compactness it is suggested to reduce the size of pivot p and the size of coil c while those current sizes are possibly minimum to almost utmost limit.